<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title></title>
  </head>
  <body>
    <script type="text/javascript">
    function ab(say){
    var say
  switch (say) {
    case 'tudou':
    console.log('哟');
    break;
        case '哟':
        console.log('你好');
       break;
       case '你好':
       console.log('想你哟');
      break;
      case '想你哟':
      console.log('一辈子不离不弃');
     break;
     case '一辈子不离不弃':
     console.log('生生世世守护你');
     break;
     case '月光倾城':
     console.log('流绪微梦');
     case '心安勿忘':
     console.log('往事随风');
    default:
  }
}
     ab('tudou');
    ab('哟');
    ab('你好');
    ab('想你哟');
    ab('一辈子不离不弃');
    </script>
  </body>
</html>
